The present disclosure is directed to an economical production method for creating the surface geometry associated with geometrically segmented abradable ceramic (GSAC) thermal barrier coating (TBC).
Components that are exposed to high temperatures, such as a component within a gas turbine engine, typically include protective coatings. For example, components such as turbine blades, turbine vanes, blade outer air seals, and compressor components typically include one or more coating layers that function to protect the component from erosion, oxidation, corrosion or the like to thereby enhance component durability and maintain efficient operation of the engine.
As an example, some conventional turbine blade outer air seals include an abradable ceramic coating that contacts tips of the turbine blades such that the blades abrade the coating upon operation of the engine. The abrasion between the outer air seal and the blade tips provide a minimum clearance between these components such that gas flow around the tips of the blades is reduced to thereby maintain engine efficiency. Over time, internal stresses can develop in the protective coating to make the coating vulnerable to erosion and spalling. The outer air seal may then need to be replaced or refurbished after a period of use.
Increasing emphasis on environmental issues and fuel economy continue to drive turbine temperatures up. The higher engine operating temperatures results in an ever increasing severity of the operating environment inside a gas turbine. The severe operating environment results in more coating and base metal distress and increased maintenance costs. For example, more frequent replacement of the outer air seals.
A coating exists called a geometrically segmented abradable ceramic, (GSAC). The GSAC in development has the potential to satisfy the above described needs in many applications, however the current manufacturing methods are very costly with many added manufacturing steps including metallic layer buildup, diffusion heat treat and CNC milling of the divot structure. There exists a need for a cost effective manufacturing process to produce GSAC.